The present invention relates to an envelope inserting machine and, more particularly, to a method and device for aligning enclosure materials, which are released from enclosure feeders and collated into a stack to be inserted into an envelope for mailing.
In an inserting machine for mass mailing, there is a gathering section where enclosure material is gathered before it is inserted into an envelope at an envelope insertion area. The gathering section is sometimes referred to as a chassis subsystem, which includes a gathering transport with pusher fingers rigidly attached to a conveyor belt and a plurality of enclosure feeders mounted above the transport. If the enclosure material contains many documents, these documents must be separately fed from different enclosure feeders.
Inserting machines are well-known. For example, U.S. Pat. No. 4,501,417 (Foster et al.) discloses an inserter feeder assembly for feeding enclosures; U.S. Pat. No. 4,753,429 (Irvine et al.) discloses a collating station; and U.S. Pat. No, 5,660,030 (Auerbach et al.) discloses an envelope inserter station wherein envelopes are separately provided to an envelope supporting deck where envelopes are spread open so as to allow enclosure materials to be stuffed into the envelopes.
An exemplary inserting machine is shown in FIG. 1. As shown, an inserting machine 10 typically includes a gathering section 12 an envelope feeder/inserter station 14. The gathering section 12 includes a plurality of enclosure feeders 20 for separately releasing documents 100. The released documents are pushed toward the envelope feeder/inserter station 14 by a plurality of pusher fingers 30, which are attached to an endless chain 32 for movement. As shown, the document 100 released by a respective enclosure feeder 20 lands on a tray 24 and then pushed off the tray 24 by an approaching pusher finger 30 onto a deck 40. As the pusher fingers 30 move forward, they collect more released documents 100. When the released documents 100, pushed by the pusher fingers 30, reach the envelope feeder/inserter station 14, they are collated into a stack (collation) 110 comprising of a plural of sheets. Thus, the gathering section 12 can also be referred to as a sheet collator. The envelope feeder/inserter station 14 includes an envelope feeder 22 positioned above an envelope insertion area 16 for releasing one envelope 200 at a time so that the stack 110 can be inserted in the released envelope 200 (see FIG. 2). Usually, the enclosure feeders 20 are arranged and aligned such that the released documents 100 are supposed to line up with each other when are collated into a stack 110. However, when a document 100 is released onto the tray 24, as shown in FIG. 2, it may not land at a designated position. It may be skewed to one side or another. Thus, even though the trailing edge of the document, where the document is pushed by the pusher finger, can be automatically aligned with the trailing edge of other documents in the stack, the side edges of the document may not be aligned with the side edges of the other documents in the stack. This may cause a problem when the stack is inserted into the envelope.
Thus, it is advantageous and desirable to provide a method and system for aligning the documents in a stack prior to the insertion of the documents into an envelope.
It is a primary object of the present invention to align the side edges of a plurality of sheets in a moving stack or collation. The object can be achieved by providing a pair of alignment devices positioned at opposite side of the moving stack to push the side edges of the sheets toward a center line of the deck of a gathering section in an inserting machine.
Accordingly, the first aspect of the present invention is an alignment system for aligning a stack having a stack width and containing a plurality of sheets, each sheet having a leading edge and two opposing side edges defining a sheet width smaller than the stack width, wherein the stack is moved along a path in a moving direction toward a downstream end. The alignment system comprising: a pair of alignment devices located at opposite sides of a center line of the path near the downstream end for pushing the opposing side edges of the sheets toward the center line, wherein each alignment device comprises a cam having an outer surface with at least one section thereof having a non-constant radius, and wherein the outer surfaces face each other to define a gate having a gate width, and a mechanism to cause the cams to rotate synchronously with respect to each other in opposite directions to change the gate width such that the gate width is greater than the stack width when the leading edge of the sheets moves into the gate, and the gate width is reduced after the leading edge has passed the gate until the gate width is substantially equal to the sheet width so as to cause the side edges of the sheets in the stack to be aligned with each other.
Preferably, each of the cams is mounted on a shaft, and the alignment system further comprises a mechanism to relocate the shafts relative to each other to adjust the gate width according to the sheet width.
Preferably, the outer surface of the cams is spiral in shape. It is also possible that the outer surface of the cams is circular in shape and each cam is rotated about an off-centered axis. It is also possible that each of the cams comprises a first circular disk rotatably mounted on a second circular disk and the cam is caused to rotate about the center of the second circular disk, wherein the outer surface of the cams is the circumference of the first circular disk. Alternatively, each cam is caused to rotate about a rotational axis and the outer surface of each cam comprises two spiral surface sections symmetrically arranged about the rotational axis.
Preferably, the sheets are moved at a constant sheet velocity by a moving means, and the cams are operatively linked to the moving means for rotation in synchronism with the movement of the sheets. It is also preferred that the cams are rotated at a constant angular velocity defining a tangential velocity at a point on the outer surface and the tangential velocity is substantially equal to the sheet velocity when the gate width is substantially equal to the sheet width.
According to the second aspect of the present invention, a method of aligning sheets in a moving stack having a stack width, wherein each of the sheets has a leading edge and two opposing side edges defining a sheet width smaller than the stack width, and the stack is moved along a path in a moving direction toward a downstream end, the method comprising the steps of:
providing a pair of alignment devices located at opposite sides of a center line of the path near the downstream end for pushing the opposing side edges of the sheets toward the center line, wherein each of the alignment device comprises a cam having an outer surface with at least one section thereof having a non-constant radius, and wherein the outer surfaces face each other to define a gate having a gate width;
causing the cams to rotate synchronously with respect to each other in opposite directions to change the gate width such that the gate width is greater than the stack width when the leading edge of the sheets moves into the gate, and the gate width is reduced after the leading edge has passed the gate until the gate width is substantially equal to the sheet width so as to cause the side edges of the sheets in the stack to be aligned with each other.
Preferably, the sheets are moved at a constant sheet velocity by a moving means and the cams are operatively linked to the moving means for rotation in synchronism with the movement of the sheets, and wherein the cams are rotated in a constant angular velocity.
According to the third aspect of the present invention, a sheet collation apparatus having an upstream end and a downstream end, the sheet collation apparatus comprises:
a moving mechanism to move a plurality of sheets in a moving path from the upstream end toward the downstream end, wherein each sheet has a leading edge and two opposing side-edges defining a sheet width;
means, located along the moving path, for collating the sheets into a stack having a stack width greater the sheet width;
a pair of alignment devices located at opposite sides of a center line of the path near the downstream end for pushing the opposing side edges of the sheets in the stack toward the center line, wherein each alignment device comprises a cam having an outer surface with at least a section thereof having a non-constant radius, and wherein the outer surfaces face each other to define a gate having a gate width, and a mechanism to cause the cams to rotate synchronously with respect to each other in opposite directions to change the gate width such that the gate width is greater than the stack width of the sheets when the leading edge moves into the gate, and the gate width is reduced after the leading edge has passed the gate until the gate width is substantially equal to the sheet width so as to cause the side edges of the sheets defining the stack to be aligned with each other.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 3a-6.